


rattle your chains if you love being free

by ratafia



Series: Kinktober 2019 [9]
Category: Ao no Exorcist | Blue Exorcist
Genre: BDSM, Bondage, Dom Yukio, Electricity, Established Relationship, M/M, Post-Canon, Public Play, Rope Bondage, Safe Sane and Consensual, Shibari, Sub Rin, Twincest
Language: English
Status: Completed
Published: 2019-10-11
Updated: 2019-10-11
Packaged: 2020-12-09 05:24:54
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,525
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20989568
Author URL: https://archiveofourown.org/users/ratafia/pseuds/ratafia
Summary: Rin needs to focus on the exam. Yukio knows just the thing to help him.





	rattle your chains if you love being free

**Author's Note:**

> Fill for the ninth day of Kinktober - Shibari. 
> 
> My knowledge of canon ends with anime, so "post-canon" goes only about what was shown there.  
Both of the boys are of age in this story.

"Undress and sit." 

Yukio put a chair in the center of their room, not even bothering to check if his orders were being followed.  
If he could trust his brother on just one thing, it would be his thirst for the things he loved. Whatever they might have been.  
So, when he turned from the closet, a bundle of ropes in hand, Rin was sitting on the appointed chair, eager and grinning, as expected. 

"That's a nice change! You're usually so serious on the day of the exams, always nagging at me to study... and..." 

Under the stern stare, Rin grew quieter and quieter with each word. He squirmed in his seat, tongue darting out to lick suddenly dry lips. He knew this kind of stare on his brother very well. This wasn't his "let's have some fun" stare.  
This was the "you messed up and now you're gonna get punished" stare.  
Rin could never decide which one of them he liked better. 

"Oh, I am serious. As you should be. I'll make sure that you will be this time." 

Well, that sounded positively devious. And kinda terrifying.  
Rin gulped as Yukio walked over, fully dressed and so composed. Distant.  
Rin's tail, that acted seemingly out of his control, always went with whatever was on his mind. This time too, it uncoiled from its usual place and reached out to Yukio, wrapping around his leg. 

"I don't remember giving you permission to touch me, big brother." 

Such a cool tone, as if he was reciting a lecture. His fingers were merciless though, digging into the sensitive appendage, the harsh grip making Rin yelp and release his hold.  
He wasn't sure what Yukio wanted him to be serious about, but if he continued that way it most certainly wouldn't be exams. 

"Now, sit still." 

That may have sounded easy, but for Rin that was one of the hardest orders of all.  
Especially when Yukio was so close, touching him.  
His concentrated expression, blue eyes not guarded by glasses for a change, the pointed ears peeking from his hair when he tilted his head to get a better angle. 

"That’s not really “sitting still”, is it, brother?" - Rin only whined in response. 

It was always like that, his energy too restless, squirming under his skin, begging to be let out.  
To move, to take, to reach its other half that was only a breath away.  
His brother, who was looking so unimpressed with him right now.  
Pinning him in place with a steely look.  
Making him want to shake out of his body with those careful touches.  
Each was deliberate, practised, without a flaw or hesitation.  
Wrapping him in thin black ropes.  
Knots and patterns, pressure and constraints.  
He hated it.  
He loved it. 

When Yukio's fingers found his tail again, he moaned, barely stopping himself not to bury his face in the shoulder right under his nose.  
Yukio didn't tell him to be quiet, right?  
He couldn't really expect that of him, not when...  
When those hands, so cruel before, were almost caressing him now.  
Wrapping something around the base of his tail, the material sticking to it firmly.  
By this point, all of his torso and arms were wrapped in rope, just tight enough to be felt, not too much to hurt.  
With every little shift they shifted too, digging in new places, not really chafing, but somehow rough enough to almost... 

Rin was so focused on the new sensations that he pretty much missed Yukio talking.  
He managed to discern only the few last words of the chant, and then there was wrenching, all consuming ecstasy racing through his body straight from whatever weird thing Yukio had put on his tail.  
Electricity.  
Just a tiny jolt probably.  
Such a little thing, yet Rin was trembling with the aftershocks of it, his poor tail writhing, trying to shake off the ring, the web snaking from it, that covered the whole length right to the tip.  
Conducting that blasted electricity, reducing Rin to the unthinking ball of lust and pain. 

"Do you like it, big brother? I made it just for you," - Rin would take the distant calm over this every day. This, that fervent whisper in his ear and deceptively soft lips on his neck, they were so much more scary than calm. - "Remember this feeling. If you don't do as I say it will activate. Anywhere. At any time. No matter who is around you." 

Yukio only laughed when he saw the blue flames.  
Rin was already calling them back, cursing himself for the moment of weakness, not wanting to ruin all the careful work his brother had done...  
Only to realise that the ropes were still right there, unharmed, they hadn’t even shifted.  
If anything, as though retaliating for the attack, they tightened, leaving Rin breathless and moaning. 

"As you can see, your flame won't be very useful here. So don't go playing with it so carelessly." 

And without further explanation, Yukio simply returned to his previous task.  
Even more ropes, each made of that strange material, were brought out and fastened around Rin.  
His chest and back, stomach and shoulders, arms all the way to his wrists.  
His thighs and legs, every inch of his body that could be covered up by clothes, was wrapped in those dark restraints. 

By the time it was finished, Rin felt like he was floating.  
He didn't try to move anymore, just allowing Yukio to arrange him as he saw fit.  
Who hummed, pleased, as he stood up, assessing his handiwork. 

"Good, very good. All, except this," - prodding fingers nudged Rin's erection, making him moan weakly, but he wasn’t in a state to talk or react past the pleading sound. - "Don't worry. I'll help you, big brother." 

And that he did.  
Gracefully, as though not affected by all of this at all, Yukio dropped to his knees, palms resting on the thighs spread before him.  
Tracing the ropes he just tied there, and answering to that touch, they tightened again.  
Just as he leaned it, with one practised motion taking the cock into his mouth and sucking.  
He wasn't bothered by the flames that burst around him, only adjusting his grip to keep Rin still.  
Looking up, intent and unblinking, drinking up the needy moans and tortured look on his brother’s face.  
As he was torn between trying to get free and thrusting up into the hot, pliant warmth of Yukio's mouth.  
His fluffy black tail tugged restlessly at Yukio's wrist, it's owner clearly too preoccupied to even try to control it.  
And then, with another jolt of electricity coursing through it, longer this time, Rin was coming, his voice bouncing off the walls, the best reward Yukio could get. 

He licked the softening cock clean, swallowing the bitter cum, not allowing even a drop to escape.  
Rin slumped in the chair, panting, whining, when the especially heavy breaths only tightened the ropes.  
Hazy eyes found Yukio, blissed out, an absolutely debauched look in them almost breaking his self-control.  
But he had to hold on.  
Just a little bit longer.  
This wasn't for him, this was for Rin. He had to take care of him.  
Today was too important to mess up. 

"Feeling better? I hope you didn't forget about the exam just yet." 

Rin blinked, groaning miserably, so relaxed just then, careless, trustingly throwing his head back in exasperation.  
So quick to bounce back from whatever life dished out on him.  
Yet still sitting, as still as he could, as he was told.  
Maybe he wasn't so helpless after all. 

"You can get dressed now, Rin," - Yukio stood up, licking his lips discreetly, chasing the taste on them. - "And don't touch those. They stay on until you're finished." 

Rin froze, his finger still stuck below one of the ropes on his belly, eyes wide and shocked. 

"Wait... You mean... Until I'm dressed?" - so naive, even after everything. 

"No, big brother. Until you finish your exam today," - Yukio couldn't hide the dark smirk that grew on his lips. - "I know better than anyone how easily you get distracted on the written ones. This will help you focus." 

It was fascinating, watching the emotions play out and shift on Rin's face. So expressive. Trusting.  
Surprise, disbelief, fear, and finally... lust.  
Exactly as he predicted. 

There was only silence after that.  
Rin did got dressed, far slower than usual, his movements not so much restricted by the ropes, as they were by the effect they had on him.  
Yukio spent countless hours perfecting them after all.  
And now they were ready.  
Following the motions of the one they were tied on. Tension adjusting to the position of the body and mental state alike.  
And of course the mental link to Yukio, their owner.  
Allowing him to monitor Rin and to take control of the bonds if need be.  
To punish.  
Or to reward. 

And they looked so exquisite too.  
Just as he had thought, the dark color contrasted brightly with the pale skin, complimenting Rin's hair.  
The slick shine of them so enticing in motion, accentuating the lines of Rin's body, it's strength and beauty.  
It was such a shame he had to watch it all disappear under the clothes, even baggier than usual to cover up the ropes.  
And the arousal that was steadily returning to Rin with each passing moment.  
Yukio only hoped it wouldn't be too much of a distraction, but a motivation, as he wanted it to be.  
To finish up, quickly, keeping focused on the task to get his reward. 

Rin stepped to him, zipping up his jacket to cover the erection straining his jeans.  
Good enough, Yukio nodded to himself.  
He didn't protest the soft kiss that Rin had asked for, tilting his chin up, cheeks flushing slightly with pleasure.  
They parted in silence still, only lingering eye contact held till the last possible moment to convey it all.  
Good luck.  
I'll be watching you.  
I'll miss you.  
I'll do my best. 

That was his intention, it really was.  
But by the time Rin arrived at the classroom the exam was supposed to be in and plopped himself at the free seat he was seriously debating his own sanity.  
And Yukio's too.  
It was torture.  
Very imaginative, and very pleasurable, yes, but still torture.  
He figured, it'd be much worse if he was human, but he wasn't.  
Rin was half-demon and his regeneration worked perfectly, not hindered by the ropes even a tiny bit.  
So there wasn't any discomfort when he moved.  
No pain too.  
If anything, it was almost... comfortable.  
He liked the feel of them, hidden from everybody, but reminding him with every breath about Yukio.  
But that exactly where the danger lay.  
Yukio, curse his four-eyed ass.  
Who knew exactly what to do to make Rin so pathetically and completely desperate.  
Who gave him this, this constant pressure driving him slowly and steadily to the needy edge, but at the same time making it the means of control.  
Exactly the means Rin wouldn't want to fight.  
Couldn't. 

He couldn't imagine it, but it actually got worse.  
Rin figured that he was being watched somehow... Yukio was good at that, keeping an eye on him no matter if they were together or apart.  
It was much easier now, with both of their powers unlocked, there was always this unseen thread, binding them together, and if he concentrated on it, Rin could feel Yukio too.  
But this time it was far, far beyond a vague feeling of awareness.  
It was like Yukio was reading his mind or something.  
The second he got distracted, boring lines of questions and his own answers blurring before him...  
The ropes reacted.  
And the worse thing about it, they reacted with the opposite of what Rin wanted.  
He figured that if he’d be inattentive, they would tighten just as they did when he disobeyed before.  
But his brother knew him too well for that.  
So every time his mind drifted, slipping into the daydream or even simply focusing on his body more than a paper on the table... The ropes went slack, still there, but too soft to be pleasant anymore.  
More like annoying, ticklish coils hanging around him, refusing to take shape until he snapped his attention back to the matter at hand.  
Only then could he feel them again.  
The knots, digging in just right, the patterns so carefully created, the tight embrace of which brought him the warmth and serenity.  
There was also that infernal thing on his tail.  
Which activated again, and again, with every page he finished.  
The first time the current came to life again, racing up his spine, he didn't manage to stifle the moan. 

"Sorry, professor... Just thinking! Mmmmhhh..." 

Looking stupid was far better than getting caught.  
Next time he was ready, biting down on his fist, riding out the intoxicating pleasure in silence.  
He thought it was just his imagination, or the oversensitivity kicking in, but by the fourth time he was sure.  
It got stronger.  
Each time the buzzing cascade of energy really grew stronger, longer too, making him writhe in his place.  
He was never so motivated to finish a damn exam.  
The moment he jotted down the last period, closing his answer sheet, he was waiting for it.  
And still not ready, the agonising current the strongest it ever was.  
Steady, unrelenting, racking through the most sensitive part of him.  
He slumped on the desk, hoping his shaking wouldn't be too noticeable, because he couldn't hold it in.  
He just couldn't, and tiny pitiful sobs were escaping him, no matter how much he tried to shut them out. 

"Okumura, I do hope you're not sleeping over there?" 

Of course it wouldn't get completely unnoticed that he was pretty much laying on his desk for a solid minute.  
Or had it been it longer? Less?  
Rin was on his last legs here, literally.  
Barely finding the strength to stand, praying that the vibrations won't return until he at least wasn’t in public anymore.  
He was almost dead so many times, impaled, crucified, blown up, and god knows what else, and yet...  
This, _this_ was the worst.  
He was totally healthy, yet he couldn't even see straight, almost tripping on the teachers desk after submitting his exam sheet.  
But he was done.  
He was finished. He did it. He had endured till the end and he finished it. 

When he exited the room, leaving behind his classmates and the last of his self-control, he already figured out where his target is.  
It was suddenly so easy to follow that thread between them, it was tugging at him, calling him, beckoning to come and get it.  
All Yukio managed, was a satisfied smile, and then he was thrown into the closest room, blue flames bright around him, licking at his clothes, reducing them to ash.  
The hungry demon with the face of his brother was smiling too.  
Dangerous, leaning in to claim another filthy kiss. 

"I hope you had your fun, Yukio... Because it's my turn now."


End file.
